Insertion head for high speed radial lead component sequencing and inserting machine

ABSTRACT

Under direction of a machine controller, an endless chain conveyor is incrementally passed by a plurality of loader heads. The loader heads receive a series of components taped on a reel supplied substrate, sever individual taped components from the supply, and load the individual taped components onto clip carriers of the endless conveyor, on command, in a preferred sequence. The clip carrier mounted components are then indexed past a cutter assembly for trimming the lengths of the leads and removing the substrate, and a positioning disc assembly for positioning the components in the clip carriers before being passed to a rotary transfer assembly. The rotary transfer assembly removes individual components from the conveyor and rotates to an unload position above a linear loader, which laterally transfers the components from the rotary transfer to an insert head assembly. At the insert head assembly, the components are oriented and inserted by their leads into the holes of a printed circuit board for clinching by a clinch mechanism. Any components still left on the conveyor after it passes the rotary transfer assembly are removed by a chain unloader.

PRIOR ART

Examples in the prior art of electronic component handling machinespertinent to the instant invention are formed in U.S. Pat. Nos.2,896,213; 3,254,821; 3,383,022; 3,455,493; and 3,777,350; as well asU.S. Pat. No. 4,203,583--"Radial Lead Component InsertionMachine"--Zemek, et al., filed May 19, 1978.

BACKGROUND OF THE INVENTION

This invention relates to a method and apparatus for selective highspeed sequencing of radial lead components onto an endless conveyor,transfer of the components to an insertion head, and insertion of thecomponents into the holes of a printed circuit board.

In the past, different methods and types of apparatus have been devisedfor sequencing, transferring, and inserting components of the abovedescribed type. These prior methods and apparatus, however, handle thecomponents by their bodies or by at least two leads. When componentswere handled by more than one lead, adjustments (requiring "down-time")needed to be made in the equipment to handle different center-to-centerlead spans.

Further, prior art devices of this nature used shuttles to pick up acomponent from one of a plurality of supply stations and transfer it toan insertion assembly. According to the distances between the supplystations and the insertion assembly the shuttle would have to travelvariable distances and therefor require variable travel times. Becauseof this, prior art devices were also limited in the amount of supplystations that could reasonably be added to the machine.

Accordingly, it is an object of the present invention to provide animproved method and apparatus for handling radial lead components ofdifferent center-to-center lead spans, in which several functions areperformed in parallel, thus providing time sharing handling of thecomponents.

It is another object of the present invention to provide transferapparatus for a sequencing and insertion machine in which all of thetransfer means are incrementally moved a fixed amount, with timesharing, thereby reducing transfer time.

It is a further object of this invention to provide an expansiblesequencing transfer means having a fixed incremental movement oftransfer.

Other objects of the invention will, in part, be obvious and will, inpart, appear hereinafter.

The above outlined objectives are accomplished by means of sequencing,transfer, and insertion apparatus which, according to the presentinvention, generally includes an endless chain conveyor for clamping andcarrying radial lead components by one lead only, and a plurality ofsupply stations for loading the components onto the conveyor chain in apreferred sequence during incremental movement of the chain. In timedrelation to the incremental movement of the chain, a Rotary TransferAssembly unloads the sequenced components, rotates and transfers thecomponents to a Linear Loader, which unloads the Rotary TransferAssembly and loads an Insert Assembly for insertion of the componentsinto a printed circuit board in a preferred orientation.

Also, in the disclosed embodiment, the length of the endless conveyorchain may be increased and the number of Sequencer Loading Heads may beincreased to provide a larger number of different type of components forsequencing and transfer.

Although more transfer stations are incorporated into the presentinvention than are used in the prior art, these various transfermechanisms are used on a time sharing arrangement to provide fasterpopulation of a printed circuit board by the insertion apparatus.

Also, by eliminating the need for the insertion head to rotate to pickup a component, the population of the printed circuit board is muchfaster.

For further understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

FIG. 1 is a right side elevational view of the overall apparatus.

FIG. 2 is a top plan (partial schematic) view of the overall apparatus.

FIG. 3 is a left side elevation (partially exploded) of the rotarytransfer assembly, insertion head assembly, and linear loader assembly,as viewed along arrows 3--3 of FIG. 2.

FIG. 4a is a schematic representation of reel supplied, substratemounted components of the radial lead type.

FIG. 4b discloses a substrate mounted component that has been severedfrom the rest of the supply.

FIG. 5 is a top plan view, partially in section, of the clip carrier ofthe endless chain conveyor.

FIG. 6 is a top plan view, partially in section, of the sequencerloading head.

FIG. 7 is a right side elevational view of FIG. 6.

FIG. 8 is a bottom plan view of the apparatus of FIG. 6.

FIG. 9 is an exploded isometric view of part of the mechanism of FIG. 6.

FIG. 10 is a sectional view of FIG. 6 along the lines 10--10.

FIG. 11 is a top plan view of the apparatus of FIG. 7 taken along thelines 11--11.

FIG. 12 is a partial schematic of the pivotal retainer arm and actuationmeans therefor.

FIG. 13 is a partial schematic view of a component being loaded into theclip carrier.

FIG. 14 is a left side elevation of the cutter assembly.

FIG. 15 is a left side partial section of the apparatus of FIG. 14.

FIG. 16a, 16b, and 17 are partial schematics disclosing the cuttingoperation.

FIG. 18 is a partial schematic of the lead translation disc.

FIG. 19 is a left side elevation of the rotary transfer mechanism.

FIG. 20 is a top plan view of the rotary transfer mechanism of FIG. 19.

FIG. 21 is a front elevation of the apparatus of FIG. 19.

FIG. 22 is a bottom plan view of the apparatus of FIG. 21.

FIG. 23 is an enlarged view of the rotary transfer head of FIG. 19partially in section.

FIG. 24 is a bottom plan view of the rotary transfer head of FIG. 23.

FIG. 25 is a partial schematic view of the rotary transfer head, linearloader, and insert head jaws.

FIG. 26 discloses the details of the sensing mechanism of FIG. 19.

FIG. 27 is a top plan view of the linear loader assembly, partially insection.

FIG. 28 is a left side elevation of the apparatus of FIG. 27.

FIG. 29 is a partial front sectional view of the apparatus of FIG. 27.

FIG. 30 is an elevational view taken along arrows 30--30 in FIG. 27.

FIG. 31 is a partial schematic view of the linear loader during loadingof the insert head assembly.

FIG. 32 is a partial schematic of the linear loader in the receiveposition and in preparation to load the insert head assembly.

FIG. 33 is a front elevation of the insert head assembly.

FIG. 34 is a right side sectional view of the apparatus of FIG. 33.

FIG. 35 is an exploded isometric partial view of the apparatus of FIG.34.

FIG. 36 is a top plan view taken along arrows 36--36 of FIG. 34.

FIG. 37 is a bottom plan view of the apparatus of FIG. 34 taken alongarrows 37--37.

FIG. 38 is a sectional view along arrows 38--38 of FIG. 34.

FIG. 39 is a partial schematic of the insert jaws of the insert headapparatus with a component held therein.

FIG. 40 is a side elevation, partially in section, of the guide jaw ofthe insert head assembly.

FIG. 41 is a detailed view of the clamping bars of the insert headassembly.

FIG. 42 is a detailed view of the cam plate of the insert head assembly.

FIG. 43 is a detailed view, partially in section, of the clamping jawsof the insert head assembly.

FIG. 44 is a left side elevational view of the chain unloader assembly.

FIG. 45 is a partial schematic of the chain unloader assembly whileunloading a component from a clip carrier.

DETAILED DESCRIPTION

One embodiment of the invention will now be described with reference tothe drawings, similar reference characters of which refer to similarparts.

In FIG. 2, a top plan view of the general positional arrangement of thevarious parts of the invention may be seen. FIG. 3 shows the RotaryTransfer Assembly 400, Linear Loader 500, and Insert Assembly 600 asviewed along arrows 3--3 of FIG. 2 but with these major component partsexploded to better show their interrelationship. FIG. 1 is a side viewof the entire apparatus, also to show the general positional arrangementof the various parts of the invention.

Referring to FIG. 2, an endless conveyor 10, having clip carriers 20, isdriven past a plurality of Sequencer Loading Heads 300 by an incrementaldrive means 30. Each of these loading heads 300 may be supplied withdifferent components from reel holder assemblies 40 or the like and areselectively fitted to load clip carriers 20 with individual componentsin a preferred sequence. The severed individual components, which mayhave tape still applied to their leads (as in FIG. 4B), are thensubjected to a cutter assembly 200 (FIGS. 14-17) to trim off the tapedportions of the leads. Thereafter, the clip carriers are passed over adriven rotating disc 50 (FIG. 18) having a beveled peripheral edge 51 toengage the bottoms of the leads of the components, thus raising them tobe flush with the undersides of the clip carriers 20.

From the disc 50, the components are carried to the Rotary TransferAssembly 400 for unloading from the clip carriers 20. For exactpositioning of clip carriers 20 relative to rotary transfer assembly400, conveyor 10 is provided with an adjustable idler 60.

A component, having been removed from a clip carrier 10 by RotaryTransfer Assembly 400, is transferred to a reciprocable Linear Loader500 that loads the component into Insert Head Assembly 600. Insert HeadAssembly 600 then inserts the component into a printed circuit boardwhich is mounted on an X-Y positioning device (not shown); a clinchmechanism (not shown) clinches the leads of component to the undersideof the circuit board. Any components that may remain in the clipcarriers 20, as during initial start-up and alignment of the machine,are removed by a Chain Unloader 800 so that the clip carriers 20 areready for reloading by Sequencer Loading Heads 300.

CLIP CARRIER (20)

Clip carrier 20 (FIG. 5) is attached to conveyor chain 10 by aconventional locking clip 21, and includes pivotal arm 22, spring biasedinto cooperative engagement with body finger 23. As seen in FIG. 5, arm22 has tapered face 24 for engagement by a component lead, duringloading of clip carrier 20 by Sequencer Loading Head 300, causing arm 22to pivot against the bias of spring 25 for reception of the lead.Another tapered face 26 allows the captured lead to open arm 22 whenbiasing pushed out of clip carrier 10 by Chain Unloader 800.

SEQUENCER LOADING HEAD (300)

Referring to FIG. 4A electronic components are frequently supplied indispencing reels 40. These reels 40 include a wound, cardboard substrate41 to which the leads of the components are taped. To facilitate feedingthe reel of components, the substrate and tape are perforated betweenindividual components as at 42.

Loading heads 300 (FIGS. 6-13) are provided to intermittently feed thedifferent taped components, sever the substrate 41 between individualcomponents, and load the severed individual components onto separateclip carriers 20 of an endless conveyor chain 10 (with the components inthe clip carriers 20 still taped to a substrate as in FIG. 4B). Thesequence in which the different components are loaded onto the conveyorand arrive at the next station is determined by a programmed control forfiring selected Loading Heads 300 on command.

Each Loading Head 300 includes a machined metal block 302 andreciprocable, fluid operated piston/cylinder 304 as a drive means forthe indexed feeding and loading. Piston/cylinder 304 is mounted on block302 by a support bracket 306 and threaded support rods 308; a fluid pipe310 supplies fluid to the front of piston/cylinder 304 for the returnstroke. The forward end of the piston of piston/cylinder 304 is threadedto clevis 312 which, in turn, is connected to a driver 314 by driverdowel 316. Driver 314 slides in a channel 318 in the top of block 302for reciprocation by piston/cylinder 304, with driver dowel 316extending downwardly through an elongate slot 320 into a generallyL-shaped recess 322 in the bottom of block 302. L-shaped recess 322 isfor accommodation of an indexing mechanism, as will be explainedfurther. The limits of travel of driver 314 are defined and adjusted bytwo stops 323, 324 threaded into block 302 and extending into oppositeends of elongate slot 320 to abut dowel 316 which reciprocates inelongate slot 320 (best seen in FIG. 8). Pivotally and slidinglyattached to the bottom end of driver dowel 316 is a link 326 to transmitthe reciprocating motion to an index pawl 328 for incremental rotationof an index ratchet 330. An anti-backup pawl 332 is also provided forratchet 330 and is attached to block 302 by an adjustable eccentric pin334 for adjustment of loose tolerances. Ratchet 330 is attached to arotary shaft 336, supported by bearings as at 335, which extends upthrough block 302 into a cut-out portion 338 in the top of block 302, asbest seen in FIG. 10.

To the top end of shaft 336 is clamped a taped component feed wheel 340having peripheral nubs 342 that engage in the perforations betweencomponents of the component supply reel. Clamping of feed wheel 340 toshaft 336 is provided by cooperating tapered rings 344, 346 held infrictional engagement between feed wheel 340 and shaft 336 by clampwasher 348 and cap screws 350.

A gate 352 is pivotally attached at 354 in order that it may be swungaway from the feed wheel 340 for alignment of the taped component supplywith feed wheel 340 during loading. After loading, gate 352 is swungback to a guiding position and held by a pin 356. A cutter support block358 is adjustably attached to housing block 302 for easy positioning ofcutter blade 360 next to driver channel 318. Supported on driver 314 isanother cutter blade 362 that cooperates with cutter blade 360 to shearindividual taped components from the incrementally advanced supplyduring the forward stroke of driver 314.

A particularly unique feature of the instant invention is the manner inwhich the individual taped components are loaded onto the conveyorchain, namely, by only one lead. This manner of loading allows theloading head 300 and the conveyor chain clip carriers to handle varioustwo-lead, taped components having different spans between their leads.Obviously, single or multiple lead, taped components also could behandled readily.

To facilitate loading these components onto the conveyor chain by onlyone lead, guide fingers 364 are provided on driver 314 to engage thefront lead of the taped components as they are halted in theirincremental feed. Guide fingers 364 engage this front lead just prior toshearing of the individual taped component from the supply. To preventthe individual component from being thrown out of engagement with guidefingers 364 (during further forward movement of driver 314 to load thecomponent into the conveyor clip carriers), a retainer arm 366 isadapted to engage the taped cardboard substrate 41 and retain the frontlead in guide fingers 364 as driver 314 moves forward and until thefront lead is loaded into the clip carrier, at which time retainer arm366 is pivoted away from the component (to the phantom line position ofFIG. 11). Referring to FIG. 13, attached to driver 314 below guidefingers 364 is a shelf 368 that provides vertical support of theindividual taped component after the shearing. In addition, an angledtop support plate 369 prevents the top of the component from bendingback onto the top of driver 314 during the forward stroke and uponcontact of the lead with the clip carrier 20 of the conveyor chain.

Retainer arm 366 is pivotally attached to a carrier 370, whichreciprocates with driver 314 during a portion of the forward andbackward stroke of driver 314; control of the pivotal action of retainerarm 366 is provided by engagement of retainer arm extension 372 withadjustable eccentric pins 374, 376 as will be explained.

Driver 314 has an orifice in which three spherical balls 378 may movetransverse to the stroke direction; the sum of the diameters of thethree balls 378 is slightly greater than the length of the orifice. Asseen in FIG. 6, a cam plate 380 is mounted on housing block 302 to theleft of driver 314, and carrier 370 is to the right. At the beginning ofthe forward stroke of driver 314, balls 378 are urged to their left-mostposition by the carrier 370. During the forward stroke, the left-mostball engages the camming surface, thus causing balls 378 to shift to theright with the right-most ball in engagement with a notch 382 in carrier370. In this manner, carrier 370 is caused to move with driver 314during the forward stroke.

Referring to FIG. 12, carrier 370 includes a nylon plunger 384 andspring 386, and retainer arm 366 has notches at 388. Plunger 384 holdsretainer arm 366 (in the position of FIG. 6) until the extension 372engages eccentric pin 374 during the forward stroke. At this time,retainer arm 366 pivots (to the phantom line position of FIG. 11) and isheld by spring biased plunger 382 until the return stroke causesextension 372 to engage eccentric pin 376 for return of retainer arm 366(to the position of FIG. 6). A spring biased detent 390 is strategicallylocated in housing block 302 for engagement with a second notch 392 incarrier 370 to stop the rearward motion of carrier 370 during the returnstroke. Placement of detent 390 and notch 392 allows carrier 370 to urgeballs 378 to the left and along the camming surface of cam plate 380while not impeding the return stroke of driver 314; proper placementalso prevents undue pressure on extension 372 by eccentric 376.Eccentric pins 374, 376 are adjustable for tolerance corrections and arelocked in their adjusted positions by a clamp 394.

For an automatic indication to the machine control of the proper feed ofa taped component to be shared and loaded, a switch assembly is provided(as seen in FIG. 11). This switch assembly includes spring biasedgrounding plate 396, mounted on cutter support block 358, which is heldin the position of FIG. 11 by the taped component supply prior toindexed advancement of a taped component to the cutting and loadingposition. When, for some reason, there is no supply to retard thebiasing of grounding plate 396, it engages a switch contact 398 tocomplete the ground of a series circuit (nominally 10 volts) and tonotify the control of an improper feed. If the loading head 300 receivesa command from the control to be fired, but the switch assembly has beenactuated by the absence of a component, the drive 30 of conveyor chain10 will halt and the head 300 will refire a set number of times (e.g.three times) to advance the feed of a component to the load position. Ifa component still has not been advanced to the load position, then boththe loading head 300 and the conveyor chain 10 will be halted.

In a prototype, the indexing of the feed wheel 340 was accomplished ascutter blade 362 just cleared cutter blade 360 during the return strokeof driver 314.

An individual taped component as in FIG. 4B is carried by conveyor 10 onclip carrier 20 to Cutter Assembly 200.

CUTTER ASSEMBLY (200)

As seen in FIG. 14, a cylinder 202 is mounted on slide housing 204, withpiston rod 206 attached by a clevis 208 to slide 210, for reciprocationof slide 210 within a passage of housing 204. The amount of forwardstroke of slide 210 is limited by an adjustable stop block 212. Abracket 213 is bolted to housing 204 and supports a die 214 and a chainguide 216 through which conveyor chain 10 is guided (for properalignment of chain 10 with Cutter Assembly 200).

Referring to FIG. 15, a cutter blade 218 and a spring biased guide 220are accommodated in a channel of slide 210. Cutter blade 218, pinned toslide 210 at 222, cooperates with die 214 (when slide 210 is extended)to provide for component lead shearing. Guide 220 is adapted to slide ontop of cutter blade 218 against the bias of compression spring 224, aswill be explained later. Vertical tang 226 of guide 220 engages the backend of cutter blade 218 (in the position of FIG. 15) to limit theforward movement of guide 220. A set screw 228 is adjustable forlimiting the vertical "play" of guide 220 and cutter 218.

Functioning of the guide 220, cutter 218, and die 214 during componentlead shearing is seen best in FIGS. 16A, 16B, and 17. FIG. 16A shows anindividual component (as in FIG. 4B) moved into position of leadshearing (for clarity, the clip carrier is not shown). As slide 210 isextended, spring biased guide 220 preceeds cutter 218 to the component.As seen in FIG. 17, guide 220 includes a finger 229 that extends betweenthe component leads (above the taped substrate 41) and into groove 230in die 214. A tapered bottom 232 of finger 229 is adapted to engage thetop of the taped substrate 41 for slight downward shifting of thecomponent in the clip carrier 20 (when necessary). Further extension ofslide 218 allows clamping of the leads of the component against die 214by guide 220, under the influence of spring 224, and shearing of thetaped heads by cutter 218 and die 214. By providing spring 224,different taped substrate and lead thicknesses may be accommodated.

After the taped portions of the leads of an individual component havebeen removed, the conveyor 10 transports the component over a drivenrotary disc 50 (FIG. 18) whose outer edge is beveled as at 51 to engagethe bottom surfaces of the remaining portions of the component leads,thus raising and properly positioning the component relative to clipcarrier 20 for presentation to rotary transfer assembly 400.

ROTARY TRANSFER ASSEMBLY (400)

Referring to FIG. 2 a Rotary Transfer Assembly 400 is adapted to clampand pick up a component from the clip carrier 20 of conveyor chain 10,rotate to a position above Linear Loader 500, lower and deposit thecomponent into Linear Loader 500, raise and rotate back to the conveyorchain 10 for pick-up of another component. This Rotary Transfer Assemblyis also adjustable to transfer components having differentcenter-to-center (CTC) spacing of the leads (such as 0.200 inches or0.300 inches CTC spacing).

The housing 402 (FIGS. 19 and 3) of Rotary Transfer Assembly 400 isadjustably attached to a C-frame support 900 (FIG. 1); housing 402 alsoserves as the means of support of the Insert Head Assembly 600. InsertHead Assembly housing 602 and rotary transfer housing 402 support LinearLoader 500 by Thompson shafts 504.

As seen in FIG. 19, rotary transfer housing 402 supports rotatable andvertically slideable rod 404 having center line 406. Verticaldisplacement piston/cylinder 408, attached to the top of housing 402 bybracket 410, has a T-nut coupling 412 with the top of rod 404. With thisarrangement, rod 404 is raised and lowered by piston/cylinder 408.

Viewing the rotary transfer assembly 400 from the top, as in FIG. 20, alever arm 414 is pinned to rod 404 at 416. Rotation piston/cylinder 418is attached to housing 402 by spherical bearing 420 and to lever arm 414by spherical bearing 422. Stroking of piston/cylinder 418 causes rod 404to rotate, with spherical bearings 420, 422 allowing piston/cylinder 418to follow the vertical motion of rod 404 when it is raised and loweredby vertical displacement piston/cylinder 408. The amount of extension ofrotation piston/cylinder 418 is adjustably limited by a stoppiston/cylinder 424 engaging lever arm 414 by neoprene bumper 426. Whenstop piston/cylinder 424 is extended (by applying fluid pressure to thepiston), rod 404 is allowed to rotate less than when piston/cylinder 424is relaxed (and retracted by a spring 428). Fine positioning adjustmentof piston/cylinder 424 is accomplished by set screws as at 430.

Referring to FIG. 26, sensing of the rotation and vertical displacementpositions of rod 404 is accomplished by Hall effect digital sensors432-435; clamped to rod 404 is holders 436, 438 for holding magnets440-443. The functional explanation of this sensing means will follow.

Also attached to rotary transfer housing 402 is sprocket 444 for guidingconveyor chain 10 with clip carrier 20 into position for rotary transferhead 460 to grasp the leads of a component that is in the clip carrier20. Head 460 is attached to the bottom of rod 404 and, upon grasping theleads of the component, is: raised by piston/cylinder 408 to remove thecomponent from clip carrier 20, rotated to a position above LinearLoader 500 by piston/cylinder 418, and lowered by piston/cylinder 408 toload the component into Linear Loader 500. After Linear Loader 500 hasreceived a component, Rotary Transfer Head 460 is raised (to clearLinear Loader 500) and rotated back to sprocket 444. This process isrepeated for successive components. Thus, when head 460 is in the "down"position at sprocket 444, switch 433 is closed by magnet 441; raisinghead 460 closes switch 432 by magnet 440 and opens switch 433; rotatinghead 460 (while in the "up" position) opens switch 433 and closesswitche 435; lowering head 460 (while in position over linear loader500) opens switch 435 and closes switch 434; raising head 460 opensswitch 434 and closes switch 435. This cycle is repeated.

Refering to FIGS. 23 and 24, head 460 comprises a main body 462, pinnedto rod 404 at 464, having a cylindrical cavity 466 for reception ofpiston 468 which extends through orifice 470 in cavity cover block 472.Piston 468 and cover block 472 retain a compression spring, as at 474. Apivotal clamp arm 476 is pivotally supported at 478 by body 462 and isbiased away from cover block 472 by compression spring 480. A bottomplate 482, with fixed clamp arm 484, is adjustably attached to body 462by set screws at 483 and to rod 404 at 486. Fluid admitted into port 488extends piston 468 into engagement with pivotal arm 476 to cause aclamping action onto component leads that are located between clamp arms476, 484 in slot 485. When fluid pressure is relieved, spring 474returns piston 468 to relieve the clamping pressure; spring 480 stillprovides light frictional engagement of the leads in clamp arms 476,484.

Refering to FIGS. 21 and 22, a nylon bearing block 490 and pivotalpressure arm 492 with roller bearing 494 aid vertical positioning ofclip carrier 20 for proper presentation of a component to head 460. Arm492 is pivotally attached at 496 (FIG. 19), with bolt 497 limiting theamount of pivot, such that roller bearing 494 is biased "up" bycompression spring 498; clip carrier 20 rides between block 490 androller 494 during presentation of a component to head 460.

The conveyor chain drive 30 is incrementally advanced so that there is adwell in movement of clip carrier 20 during presentation of thecomponent to head 460. The relative positioning of sprocket 444 and head460 is such that components of different center-to-center lead spans maybe accommodated. For instance, components may be used with spans of0.200 inches or 0.300 inches, the first lead presented to slot 485always entering slot 485 a certain amount (nominally 0.015 inches) fromthe back end 489 of slot 485 before clamping takes place. In thismanner, the first lead is always in a fixed position relative to head460. Stop piston/cylinder 424 (which limits the amount of rotation ofhead 460) is used to vary the positioning of head 460 such that thecomponent leads straddle the centerline 544 of Linear Loader 500.

LINEAR LOADER (500)

The Linear Loader of FIGS. 27-30 includes a carriage 502 which rides onThompson shafts 504 and is reciprocated on these shafts 504 between a"receive" position and a "discharge" position by piston/cylinder 506. Inthe "receive" position, linear loader 500 receives a component (by theleads) from rotary transfer head 460; in the "discharge" position,Linear Loader 500 loads the component (again, by the leads) into InsertHead 600. Piston/cylinder 506 is clamped onto Thompson shafts 504 byintegral clamping wings 508 which are tightened down by hex screws orthe like. An angled digital sensor support bracket 510 is bolted to oneside of piston/cylinder 506 at 512 and supports two spaced Hall effectswitch digital sensors 514, 515. Another angled support bracket 516 hastwo spaced magnets 518, 519 clamped thereto and is bolted onto carriage502 at 520 such that bracket 516 passes near to bracket 510 during thereciprocation of carriage 502. With this arrangement, magnet 518 isopposed to sensor 514 when carriage 502 is in the "receive" position,and magnet 519 is opposed to sensor 514 when carriage 502 is in the"discharge" position.

Piston rod 522, attached to the piston of piston/cylinder 506 is reducedin diameter at 524 (FIG. 29) to form an abutment for one end of acompression spring 526, the other end of spring 526 abutting the end 528of bore 530 in carriage 502. The purpose of spring 526 will become clearfrom the following description. Bearing 532 keeps the reduced portion524 of piston rod 522 centered in bore 530. As seen in FIG. 28, agenerally U-shaped bracket 534 is bolted to the end of reduced portion524 at 535 and has rods 536 extending across the "U" of the bracket.

For extension of piston rod 522, 60 pounds and 80 pounds of air areapplied to respective ports 538, 539. For retraction, 60 pounds of airis applied to only port 538. During extension, due to the differences inthe air pressure admitted and the differences in face areas on each sideof the piston, a low level net force for extension of rod 522 isprovided. As this extension begins, a regulator (not shown) in port 538maintains 60 pounds of air pressure on the rod side of piston/cylinder506 throughout the forward stroke. When sensor 514 is actuated by magnet519 (near to, but not at full stroke of the piston) and at the point oftravel of carriage 502 at which bumpers 540 contact adjustable screws542 (mounted on insert head housing 602 as seen in FIG. 27), the 60pound air pressure is completely evacuated. Eighty pounds of airpressure (still on the piston side) then causes full stroke andcompression of spring 526. Thus, with the regulated evacuation of 60pounds of air pressure from the rod side of piston/cylinder 506, thefull brunt of the forward stroke (acting against the inertia of carriage502) does not sufficiently compress spring 526 to defeat its purpose ofspacing the carriage 502 relative to rod 522 until screws 542 havehalted forward travel of carriage 502.

Each side of the centerline 544 of carriage 502, and any attachmentthereto, is a mirror image of the other side of the center line 544(except for the already described magnet support bracket 516 added toone side); therefore, a description of one side of the centerline 544will suffice.

The top face of carriage 502 is channeled to receive laterallyreciprocable slide 546. Slide 546 has a slot 548 and arms 550, 551 (FIG.28) extending upwardly above the top face of carriage 502. Straddlingslide 546 and bolted to carriage 502 as at 552 is a slide retainingplate 554.

Attached by machine screws to arm 550 of slide 546 are clamp jaw 556 andguide jaw 558. Clamp jaw 556 has a reduced thickness to afford slightlateral flexure away from centerline 544. Guide jaw 558 is cut awayalong the length thereof to provide a gap between it and clamp jaw 556in which a pusher plate 560 (best seen in FIGS. 29 and 32) reciprocatesparallel to centerline 544. Pusher plate 560 is slidingly supported byrods 536 and has a step 561 notched out of one corner of the plate.Guide jaw 558 and clamp jaw 556 have cooperating depressions 563 (as ifa solid cone was cut out of their top surfaces with guide jaw 558 andclamp jaw 556 side-by-side) to guide the reception of a component leadinto step 561 of pusher plate 560 when the carriage is in the "receive"position.

Carriage 502 has a lateral adjustment for accommodating componentshaving different lead spacings (i.e., 0.200" or 0.300"). To facilitatethis adjustment (again, explaining only one side of carriage 502),cylinder 564 has been bored in the body of carriage 502 for reception ofpiston 566. Piston rod 568 extends out of cylinder 564 and is attachedby a machine screw to vertical plate 570 which, in turn, is bolted toarm 551 of slide 546. In this manner, stroking of piston 566 causesreciprocation of slide 546; the reciprocation of slide 546 is limited bypost 572 which is press-fit into the channeled face of carriage 502 andextends upwardly into sliding engagement with slot 548. The limits oftravel of slide 546 are determined by the length of slot 548 (nominally,allowing 0.050 inches of travel of slide 546 for a 0.100 inch change).By controlled stroking of piston rod 568, guide jaw 558 and clamp jaw556 are adjustable toward or away from centerline 544 with consequentlateral sliding of pusher plate 560 along rods 536 for compensation ofdifferent center-to-center component lead spans.

In operation, with carriage 502 in the "receive" position and adjustedfor a particular lead spacing, Rotary Transfer Assembly 600 lowers acomponent to allow the leads to engage depressions 563 and be guidedinto frictional engagement between guide jaw 558 and clamp jaw 556 andonto step 561, at which time Rotaty Transfer Assembly 600 unclamps,raises up, and pivots away (this position is best seen in FIGS. 31 and32). Forward stroking of piston/cylinder 506 drives loaded pusher plates560 to the "discharge" position (at Insert Head Assembly 600). Untilcarriage bumpers 540 engage screws 542 to halt forward movement ofcarriage 502, the leads are still held frictionally between guide jaws558 and clamp jaws 560; upon this engagement of bumpers 540 and screws542, carriage 502 is halted and pushers 560 push the leads of thecomponent into frictional engagement with gripper assembly 670 (ofInsert Head Assembly 600, as described in the next section). Thecarriage 502 is then returned to the "receive" position, as describedabove.

For cushioning the return of carriage 502 to the "receive" position,compression springs 574 (encompassing Thompson shafts 504) areinterposed between carriage 502 and clamping wings 508. A set screw andlock nut arrangement 543 limits the return of carriage 502 during theback stroke of piston/cylinder 506.

Upon being loaded into Insert Head Assembly 600, the component is readyto be positioned and inserted into the printed circuit board.

INSERT HEAD ASSEMBLY (600)

Referring to FIGS. 34 and 35, insert head assembly 600 includes fixedhousing 602 having three (3) laterally reciprocable guide rods 604spaced 60° apart around the periphery of a rotatable, reciprocable guidetube 606 (as seen in FIG. 34) for selective engagement of guide rods 604into respective guide arrows of guide tube 606. Each guide rod 604 isrotatable upon its own longitudinal axis, with a spring 610 forextension and a pneumatic piston/cylinder 612 for retraction. Bearings614 are provided for the rotational support of guide rod 604 and arespaced apart along the axis of guide rod 604 by spring 616. Each guiderod 604 is loosely, yet fixedly, engaged on the outside end to a piston613 of the guide rod assemby piston/cylinder 612. By pneumatics, thispiston 613 retracts guide rod 604 against the positive action of spring610 when air is applied; when no air is applied, the piston 613 isextended by spring 610.

Referring to FIG. 35, the outer face of guide tube 606 has three guidegrooves 620, 621, and 622. Center guide groove 621 is arranged parallelto the axis 624 of the guide tube 606 such that tube 606 may onlydisplace vertically with the corresponding guide rod 604 engaged in thisgroove 612; the other two guide grooves 620, 622 are oppositely helixedsuch that the guide tube will rotate a total of ±90° during a completereciprocation between the "up" and "down" positions.

Complete reciprocation of guide tube 606 is accomplished by a "verticalpiston/cylinder" 626 mounted on the same support 628 as housing 602. Tothe upper end of guide tube 606 is secured a thrust block 630 by machinescrews such as 632. This thrust block 630 receives and retains the lowerend of a rod 634 (to which to attached the piston of "verticalpiston/cylinder" 626) and is tooled to a tolerance that allows it torotate about the longitudinal axis 624 during reciprocation of rod 634.

Attached to the top end of rod 634 is a threaded clamp collar 738. Byadjusting threaded clamp coller 638 longitudinally on rod 634, thelength of stroke of the "vertical piston/cylinder" 626 may be set.

Mounted on the upper end of "vertical piston/cylinder" 626 is a "partialretract piston/cylinder" 640, the piston of which slideably encompassesthe upper end of rod 634. The upper end 642 of this piston extends outof its cylinder such that a neoprene bumper 644 engages it when rod 634is in the extreme "down" position. The working surface area of thepiston of "partial retract piston-cylinder" 640 is larger than that ofthe piston of "vertical piston/cylinder" 626. With these differentsurface areas, rod 634 (when in the extreme "down" position under theaction of "vertical piston/cylinder" 626) may be partially retracted"up" (nominally one quarter inch) by the piston of "partial retractpiston/cylinder" 640 in engagement with bumper 644, while applying thesame air pressure to both piston/cylinders 626 and 640.

Referring to FIGS. 33 and 34, two Hall effect switches 646, 647 aremounted along the line of travel of rod 634; a permanent magnet 648 ismounted upon the extreme upper end of reciprocable rod 634. These Halleffect switches 646, 647 are common in the industry and are manufacturedby SPRAGUE as types UGN-3220S and UGS-3220S. Switches 646, 647 are usedto indicate the respective extreme "up" and "down" positions of rod 634.

The upper end of rotatable, reciprocable guide tube 606 has an enlargedrecess 650 to form the cylinder of a drive piston/cylinder of which thepiston 652 includes hollow piston rod 654 telescoping inside guide tube606. The lower end of hollow piston rod 654 has a nub 656 for a purposeyet to be explained. Hollow piston rod 654 is extended downwardlyrelative to guide tube 606 when air is supplied to extension air inlet635 and is retracted upwardly relative to guide tube 606 when air issupplied to the bottom of piston 652 at retraction air inlet 636. Accessof air from inlet 635 to the top of piston 652 is via bore 619 of FIG.34. Referring to FIG. 35, access of air to the bottom of piston 652 fromretraction air inlet 636 is via plate hole 637, bore 617 in the body ofguide tube 606 (parallel to axis 624), and cross-bore 618 in the body ofguide tube 606 (perpendicular to axis 624). A plug (not shown) seals theintersection of cross-bore 618 and the outer surface of guide tube 606.

An insert plunger 658 is telescopingly received in hollow piston rod 654and is slotted at 660. A pin 662 has a force fit connection with pistonrod 654 and is adapted for sliding engagement with slot 660 of plunger658 to provide limits for telescoping of plunger 658. Abutting the upperend of plunger 658 is the lower end of compression spring 664, the upperend of which abuts a plug 666. In this manner, with nothing elseaffecting plunger 658, spring 664 biases plunger 658 to an extendedposition.

Guide tube 606 includes pivot pins 668 (perpendicular to longitudinalaxis 624) for pivotally supporting a gripper assembly 670. Referring toFIGS. 34, 35, 39, 40, gripper assembly 670 includes a U-shaped trough672 with the axis 673 of trough 672 angled (nominal 10°) away fromlongitudinal axis 624. The sides of trough 672 have projecting tangs 674and raised fins 676 (for a purpose yet to be explained). Extendingdownwardly and angling toward longitudinal axis 624 is guide jaw 678.Pins 680 and 682 act as supports and lateral guides for leaf jaws 684 oneach side of guide jaw 678. bore 686 in guide jaw 678 is for receptionof a compression spring 688 that biases leaf jaws 684 away from guidejaw 678 to the "open" position. Extending through guide tube 606 is arotatably adjustable eccentric rod 690 adapted to limit pivoting ofguide jaw 678 toward longitudinal axis 624. A tension spring 692 isattached at one end to a pin 694 in the body of guide assembly 678 andat the other end to eccentric rod 690, thus biasing guide jaw 678 awayfrom longitudinal axis 624. Dowels 695 are attached to both sides ofguide tube 606 and extend into a pair of clamping bars 698 to looselyretain these clamping bars 698 (perpendicular to longitudinal axis 624)to prevent them from falling out of guide tube 606. Set screws 700 (foradjustment of clamping) are threaded into clamping bars 698 and extendinwardly into engagement with the outside surfaces of leaf jaws 684.Each bar 698 (FIG. 41) has bevelled portions 704 and a flat portion 706,for purposes yet to be explained.

A cam plate 708 (FIG. 42) is adapted to slide up and down under theinfluence of piston rod 654 and has flats 710 and a machined channel 712extending substantially the entire length of plate 708. At the upper endof cam plate 708 on each side of channel 712, are two inclined camsurfaces 714 at the lower end are notches 716 forming ears 718 and earcam surfaces 720. Channel 712 receives nub 656 of piston rod 654 forsliding engagement until nub 656 abuts the upper or lower end of channel712.

With the gripper in the position of FIG. 34, hollow piston rod 654 is inthe raised position and nub 656 prevents cam plate 708 from slidingdownwardly. The fins 676 of guide jaw bear against flats 710 of camplate 708 under the bias of tension spring 692. Flat portions 706 ofclamping bars 698 are engaged with ears 718 of cam plate 708 to clampthe leaf jaws 684 closed.

When hollow piston rod 654 is extended downwardly, nub 656 slides inchannel 712 until it engages the lower end of channel 712. Continueddownward movement of rod 654 forces cam plate 708 downward so that fins676 of the gripper ride down incline cams 714 (allowing guide jaw 678 topivot away from longitudinal axis 624), and clamp bars 698 ride intonotches 716 under the influence of compression spring 664 (to allowopening leaf jaws 684 by spring 688).

Retraction of hollow piston rod 654 causes nub 656 to slide upwardlyuntil it abuts the upper end of channel 712. Continued upward movementof rod 654 forces cam plate 708 upward so that fins 676 of the gripperride up incline cams 714 (allowing guide jaw 678 to pivot towardlongitudinal axis 624); ear cams 720 ride on bevels 704 of clamps bars698 until ears 718 engage flat portions 706 (to close leaf jaws 684).

Referring to FIG. 43 for the jaw configuration of gripper assembly 670,it can be seen that guide jaw 678 has notches 722 and tapered portions724; leaf jaws 684 each have an inset surface 726 angling out to anobtuse corner 728, and then tapered back again at 730. When leaf jaws684 and guide jaw 678 are arranged side-by-side as shown in FIG. 43,each obtuse corner 728 extends slightly into each notch 722; notches 722and insets 726 form a slot in which components leads can be held by aninterference fit. Tapers 730 allow easier sliding of leads into theslots and obtuse corners 728 retain the leads in the slots. In theunclamped position of the jaws, the clearances of obtuse corners 728 areslightly less that the outside diameter of each lead, such that leafjaws 684 are flexed outwardly by engagement of the leads with obtusecorners 730 during their reception. When the leaf jaws 684 are clamped,the leads are securely held in notches 722 by inset surfaces 726.

As seen in FIG. 37, engagement or disengagement of a guide rod (604) inone of the guide grooves (620, 621, 622) is sensed for control purposes.To facilitate this sensing, piston (613) has a extension 732 with apermanent magnet 734 clamped to it; magnet 734 cooperates with HallEffect digital sensor 736 to indicate the extended or retracted positionof guide rod (604).

CHAIN UNLOADER (800)

FIG. 44 shows Chain Unloader 800 comprising a fairly flexible metalejector 802 attached to reciprocation piston/cylinder 804. An angledmounting bracket 806 mounts the device so that ejector 802 is at anangle to clip carrier 20. Preferably, bracket 806 is adjusted so thatejector 802 engages the top face of clip carrier 20 just prior toengagement with the component lead (as seen in FIG. 45). With thisarrangement, extension of ejector 802 pushes the component out of clipcarrier 20. A bin (not shown) is provided to catch the unloadedcomponents.

It will thus be seen that the objects set forth above, among those madeapparent from the preceeding description, are efficiently attained and,since certain changes may be made in carrying out the above method andin the construction set forth without departing from the scope of theinvention, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention, which, asmatter of language, might be said to fall therebetween.

Now that the invention has been described what is claimed as new anddesired to be secured as Letters Patent is:
 1. In an apparatus forcyclical insertion of radial leads of electronic components into theholes of a printed circuit board upon command, said apparatus includinggripper means for gripping the leads of a component and pivoting about apivot axis perpendicular to the longitudinal axis of the apparatus,drive means for actuating said pivotal gripper means, and a plunger forengaging the body of said component to drive the leads into said holes,the improvement comprising:a guide tube vertically displaceable alongand rotatable about said longitudinal axis and supporting said pivotalgripper means, said longitudial axis fixed vertically; displacementmeans for vertical displacement of said guide tube along saidlongitudinal axis; guide means for determining rotating or straight linemovement of said guide tube along said longitudinal axis during verticaldisplacement of said guide tube; first sensor means for sensing thevertical displacement of said guide tube; and a guide jaw extendingdownwardly from a main body and flexible leaf jaws cooperating with saidguide jaw to provide slots of a configuration suitable for receivingsaid leads in a flexible interference fit relation during said receivingand prior to said gripping such that shifting of said leads is avoided.2. An apparatus as in claim 1, wherein said main body is pivotal aboutsaid pivot axis between an insert position and a lift-off position andcomprises tang means engageable with an adjustable eccentric when insaid insert position, whereby said eccentric limits the pivoting of saidmain body to said insert position and is adjustable for alignment of aplane, defined by two clamped leads, with said longitudinal axis.
 3. Anapparatus as in claim 2, wherein said plunger is spring biased tocompensate automatically during insertion for components havingdifferent body heights.
 4. An apparatus as in claim 2, wherein saidguide tube and said guide means are engaged to cause rotation about orstraight line movement along said longitudinal axis during verticaldisplacement of said guide tube.
 5. An apparatus as in claim 4, whereinsaid apparatus further includes a second sensor means for indicating theengagement of said guide means and said guide tube.
 6. An apparatus asin claim 2, wherein said apparatus further includes a spring meansattached to said eccentric and to said main body for biasing said mainbody to said lift-off position.
 7. An apparatus as in claims 2, whereinsaid main body further includes laterally extending leg means forengagement by a cam plate vertically displaceable along saidlongitudinal axis to pivot said main body to said insert position.
 8. Anapparatus as in claim 6, wherein said gripper means furthercomprises:spring means for biasing said leaf jaws toward a leafunclamping position; clamp bar means, engaged with said leaf jaws andengageable by said cam plate, for urging said leaf jaws to a leadclamping position, said clamp bar means having means for adjusting alead clamping pressure applied by said leaf jaw.